The present invention relates to a bale-forming device in general, and more particularly to a bale-forming device for agricultural uses.
There have already been proposed various devices of the latter type. So, for instance, there is already known a bale-forming implement equipped with a bale-forming charging arrangement. This conventional agricultural implement includes walls which delimit a baling chamber which has an inlet end at the front, and an outlet end at the rear, of the implement as considered in the advancement direction thereof. Then, there is provided an inlet opening in the bottom of the baling chamber at the inlet end thereof which extends substantially over the entire width of the baling chamber. This implement further has equipment which picks hay or a similar crop up from the ground during the movement of the implement and which delivers the picked-up crop material into a guiding channel which communicates with the inlet opening. In the guiding channel, a respective charge of the picked-up material is advanced through the guiding channel into the inlet end of the baling chamber by packing fingers or prongs so that a bale is formed at the inlet end of the baling chamber and advances, as further charges are advanced by the packing fingers from the guiding channel into the inlet portion of the baling chamber, toward the outlet end of the baling chamber. Furthermore, this implement is equipped with means for tying the fully formed bale still in the baling chamber.
A device of the above-discussed type is disclosed, for instance, in the German published patent application No. 1,782,382. In this device, the material to be baled is advanced into the baling chamber by an oscillating advancing arrangement, at considerably different pressures. This is attributable to the fact that, at the commencement of the formation of a new bale, the previously formed bale is first pressed by the following material out of the baling chamber. The pressure exerted on the material being baled by the oscillating advancing arrangement is not very high inasmuch as an outlet door arranged at the rear end of the implement is open under these circumstances and the previously formed bale can be shifted out of the baling chamber without offering much resistance to such shifting. As soon as the previously formed bale leaves the baling chamber and the rear door or flap is again closed, the pressure exerted on the newly forming bale decreases further at first and increases only after the baling chamber has been filled with the crop material. The highest pressure, which is delimited by the strength of the device and the available power input, is achieved only during the end phase of the formation of the bale. During this end phase, the material being baled is compacted at the packing fingers to such extent that its structure is changed and thus its expansion capacity is considerably attenuated. However, the material which has been so pre-compressed to a high density takes up only about one-fourth of the volume of the bale. Inasmuch as the pressure which is exerted by the packing fingers on the material of the bale is not uniformly distributed throughout the baling chamber, the remaining material retains a lower density and a high expansion capacity, which results in a high loading of the tying twine or twines after the bale has been discharged from the baling chamber. This, of course, is very disadvantageous. An additional disadvantage of the above-discussed prior-art device is that, due to the non-uniform density of the bale the latter will contain much less of the crop material than could be otherwise accommodated in the same space.